Subunit II (b') and not subunit I (b) of photosynthetic ATP synthases is equivalent to subunit b of the ATP synthases from nonphotosynthetic eubacteria. Evidence for a new assignment of b-type F0 subunits.
Subunit I of chloroplast ATP synthase is reviewed until now to be equivalent to subunit b of Escherichia coli ATP synthase, whereas subunit II is suggested to be an additional subunit in photosynthetic ATP synthases lacking a counterpart in E. coli. After publication of some sequences of subunits II a revision of this assignment is necessary. Based on the analysis of 51 amino acid sequences of b-type subunits concerning similarities in primary structure, isoelectric point and a discovered discontinuous structural feature, our data provide evidence that chloroplast subunit II (subunit b' of photosynthetic eubacteria) and not chloroplast subunit I (subunit b of photosynthetic eubacteria) is the equivalent of subunit b of nonphotosynthetic eubacteria, and therefore does have a counterpart in e.g. E. coli. In consequence, structural features essential for function should be looked for on subunit II (b').
Tiburzy
H J
HJ
Lehrstuhl für Biochemie der Pflanzen, Fakultät für Biologie, Ruhr-Universität Bochum, Germany.
Berzborn
R J
RJ
D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000201:enzymology; D002736:Chloroplasts / Q000201:enzymology*; D004926:Escherichia coli / Q000201:enzymology; D005056:Euglena gracilis / Q000201:enzymology; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010788:Photosynthesis; D010944:Plants / Q000201:enzymology; D006180:Proton-Translocating ATPases / Q000737:chemistry*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D046911:Macromolecular Substances; D006180:Proton-Translocating ATPases